This is a proposal to purchase and operate a hybrid quadrupole-time of flight mass spectrometer in the Biomolecular Mass Spectrometry Laboratory of the University of Louisville (UofL). No such high resolution, accurate mass spectrometry for is available now at the UofL or in the region. The Specific Aims of this Proposal are as follows: provision of (1) High resolution, accurate tandem mass spectrometry capabilities for qualitative identification of biologically relevant molecules. (2) Enabling of high sensitivity structural analysis of (2) modified DNA and RNA, (b) post-translational modifications of proteins and (c) non-covalent protein-protein or protein-nucleic acid interactions as biological control mechanisms or markers of xenobiotic toxicity. (3) Enabling of development of quantitative techniques for study of biological control mechanisms at the molecular level. (4) Implementation of an education program for research development and scientific career development. Four Major Users Research Focus Groups have been identified, including 16 Major Users funded by 8 different Institutes of the NIH. The specific applications are quite varied, but are focused in one of four areas in which hybrid Q-TOF technology has been successfully integrated: (1) Cell-cell communications: Signaling and Post- translational modifications, (2) Oxidative processes in pathology and toxicology, (3) Functional Genomics and Proteomics and (4) Molecular Endocrinology. These research scientists will benefit immediately from availability of the Q-TOF for the projects already deemed scientifically important by NIH review, and will have flexible options for user access. An educational outreach strategy will recruit other NIH funded users to incorporate this technology. The University of Louisville makes a strong commitment in support of this application, with an overall value of twice the funds requested. A detailed mechanism is described for efficient management and use of the instrument. The University also commits to paying for the costs of setup, installation, maintenance and support personnel. The commitment of the University is made for a period of five years. The Principal Investigator will rely on advice from a Technical Advisory Group and an Internal Advisory Committee, the composition of which is specified in the proposal. This project will allow these investigators and others to break through a technical roadblock to have their requirements met by in-house analytical capability.